The invention relates to a miniature electrical switch whose design has been studied so as to reduce the number of parts and the assembly time, with a view to lowering its cost price and increasing its reliability.
The miniaturization of electromechanical devices gives rise to considerable problems of reliability and cost price. The fragility of the components, their number, the difficulties of assembly are the principal obstacles which oppose an improvement in the quality/price ratio. Several constructors market at the present time miniaturized electrical switches having typically ten positions, comprising two pushers, respectively for counting up and counting down. Such a type of switch comprises a plastic case which houses the two pushers, as well as a wheel carrying one or more metal brushes in rubbing contact with a printed circuit on which are set the fixed studs of the switch. The printed circuit forms advantageously one of the walls of the case. The wheel bears figures on its cylindrical surface, visible through a window in the case. A drive gear is integral with this wheel and each pusher, movable in translation within the case, carries a tooth capable of engaging with said drive gear so as to cause the wheel to turn in a corresponding direction of rotation. For that, the two pushers are arranged symmetrically on each side of the wheel. A return means is inserted between the end of each pusher and the bottom wall of the case, to urge said pusher away from said gear. The return means is, generally, a small helical spring whose positioning in the case during assembly is a delicate operation. The invention aims more especially at doing away with such helical springs.